1. Field of the Invention
The invention relates to a method for gluing a friction lining to a support by means of an adhesive that develops its full adhesive effect under the influence of pressure and/or temperature. The invention further relates to a tool for sticking a friction lining to a support by means of an adhesive. The invention further relates to a tool for stacked gluing of supports comprising friction linings that have been stuck to the supports.
2. Description of Prior Art
It is known from German patent specification DE 44 31 642 B4 to connect a friction lining to a support when producing a preform. The support can be connected to the finished lining during the course of a hot pressing procedure or by means of a separate gluing process. The object of the invention is to improve the gluing of friction linings to supports by means of an adhesive.
With a method for gluing a friction lining to a support by means of an adhesive that develops its full adhesive effect under the influence of pressure and/or temperature, the object is achieved in that the friction lining and the support are pressed together along with the adhesive before the adhesive develops its full adhesive effect in order to stick the friction lining to the support. When affixing the friction lining to the support, the friction lining is pre-fixed to the support. The friction lining is then only ultimately fixed to the support when the glue develops its full adhesive effect. The glue develops its full adhesive effect in a subsequent crosslinking or curing process under the relatively prolonged influence of a higher temperature compared with during the affixation of the friction lining to the support. To affix the friction lining to the support, the adhesive is only subject over a short period to a high pressure and a lower temperature than when curing or crosslinking. The friction lining is preferably a clutch friction lining of a dry friction clutch, in particular a double clutch. The support is preferably a sheet metal support. The friction lining is preferably coated with adhesive.
A preferred exemplary embodiment of the method is characterized in that the adhesive is made to flow under the influence of pressure and/or temperature, before the adhesive develops its full adhesive effect. The flowing adhesive distributes optimally between the support and friction lining. The flowing adhesive particularly advantageously penetrates, in part, the preferably porous friction lining. During this process, the pressure and/or the temperature is/are set such that the adhesive does not yet crosslink or cure. The adhesive only crosslinks or cures after the affixing process, at a much higher temperature over a longer period of time.
A further preferred exemplary embodiment of the method is characterized in that the support and the friction lining are positioned and/or centered relative to one another before being pressed together. The support and friction lining are preferably positioned and/or centered in a special pressing tool. During the process, the support and friction lining are positioned relative to one another in particular in the circumferential direction.
A further preferred exemplary embodiment of the method is characterized in that a plurality of friction linings stuck to supports are pressed together in a stacked-gluing process, wherein the adhesive develops its full adhesive effect. In the case of stacked gluing, the friction linings already stuck to the supports are pressed together at a high temperature over a longer period of time than during the previous affixing process, such that the adhesive crosslinks or cures. The pressure during crosslinking or curing is lower than when affixing the friction linings.
With a tool for sticking a friction lining to a support by means of an adhesive, in particular by a method described above, the problem stated in the introduction is achieved in that the tool has a lower tool plate and an upper tool plate, between which the friction lining and the support are pressed together along with the adhesive. The terms “lower” and “upper” relate to the direction of action of the force of gravity. The friction lining is preferably coated with the adhesive. However, it is also possible to coat the support, or the support and the friction lining, with the adhesive. The two tool plates are preferably installed in a C-frame press, with which the required pressure for affixing the friction lining to the support can be applied. A heating plate is installed in the tool plate, which contacts the support, in order to introduce into the tool the heat required to affix the friction lining to the support.
A preferred exemplary embodiment of the tool is characterized in that the lower tool plate has centering pins for the friction lining and centering pins for the support. The centering pins are used to position and/or center the friction lining and the support relative to the tool and relative to one another.
A further preferred exemplary embodiment of the tool is characterized in that the centering pins taper conically at their free end. The centering and positioning of the friction lining and the support is thus facilitated, such that the process can be automated.
A further preferred exemplary embodiment of the tool is characterized in that the centering pins are guided movably in the lower tool plate in their longitudinal direction and are biased by a spring in the direction of the upper tool plate. The positioning and centering of the support and friction lining is thus further facilitated. The tool according to the invention is preferably combined with further tools in a round plate facility.
A further preferred exemplary embodiment of the tool is characterized in that the centering pins for the support have an outer diameter that is different from that of the centering pins for the friction lining. Corresponding through-holes for the centering pins are provided in the support and in the friction lining. The friction lining is preferably positioned and centered first on the lower tool plate. During this process, a through-hole in the friction lining for the centering pin of the support is left open.
With a tool for stacked gluing of supports comprising friction linings that have been affixed to the supports in particular by a method described above, in particular using a tool described above, the above-stated object is achieved in that the tool for stacked gluing has centering rods, which are arranged radially to the outside of the friction linings stuck to the supports in order to position and/or center these friction linings between two press plates. A total of four centering rods are preferably guided into the corner regions of the preferably square press plates. Further positioning pins, which extend through the supports or friction linings, can be omitted. In the case of stacked gluing, the previously affixed friction linings are connected fixedly to the friction linings by applying pressure and high temperature over a relatively long period of time, wherein the adhesive cures or crosslinks.